ARM Template custom config for Hostpool provisioning is not working

I tried to use the example ARM templates to apply the Virtual desktop optimization tool. It´s not working. the portal error message is "the location property is reequired for this definition".
However, parameter file contains the location and the ARM template reference the correct parameter. Not sure if this is a bug.

Start with the example ARM templates and their parameter file, then reproduce the Hostpool provisioning attempt in the Azure portal to capture the location error. Compare how the location value is supplied to the custom configuration and confirm the deployment succeeds without the validation error.

Written by the indexing model from the issue text.